double类型的框架必须在0到1的范围内：MATLAB

我有一个视频，并已在MATLAB上为其制作了Sobel蒙版。现在，我必须通过for循环读取每一帧，将Sobel蒙版应用于视频的每一帧。该过程类似于：

• 步骤1：阅读框架。
• 第2步：使用将其转换为灰度rgb2gray。
• 步骤3：将其转换为两倍。

在这里，当我尝试在结果video.avi文件上写入框架时应用了蒙版后，出现以下错误：

“类型的框架double必须在0到1的范围内”

我的代码有什么问题？我编写的代码如下所示：

vid = VideoReader('me.mp4');
frames = read(vid);
total = get(vid, 'NumberOfFrames');
write = VideoWriter('me.avi');
open(write);
mask1 = [-1 -2 -1; 0 0 0; 1 2 1]; % Horizontal mask
mask2 = [-1 0 1; -2 0 2; -1 0 1]; %Vertical Mask
for k = 1 : 125
    image = frames(:,:,:,k);
    obj = image;
    obj1 = rgb2gray(obj);
    obj2=double(obj1);
    for row = 2 : size(obj2, 1) - 1
        for col = 2 : size(obj2, 2) - 1
            c1 = obj2(row - 1, col - 1) * mask1(1 ,1);
            c2 = obj2(row - 1, col) * mask1(1 ,2);
            c3 = obj2(row - 1, col + 1) * mask1(1 ,3);
            c4 = obj2(row, col - 1)*mask1(2, 1);
            c5 = obj2(row, col)*mask1(2, 2);
            c6 = obj2(row, col + 1)*mask1(2, 3);
            c7 = obj2(row + 1, col - 1)*mask1(3,1);
            c8 = obj2(row + 1, col)*mask1(3,2);
            c9 = obj2(row + 1, col + 1)*mask1(3,3);
            c11 = obj2(row - 1, col - 1)*mask2(1 , 1);
            c22 = obj2(row, col - 1)*mask2(2, 1);
            c33 = obj2(row + 1, col - 1)*mask2(3, 1);
            c44 = obj2(row -1, col)*mask2(1, 2);
            c55 = obj2(row, col)*mask2(2 , 2);
            c66 = obj2(row +1, col)*mask2(2 , 3);
            c77 = obj2(row - 1, col + 1)*mask2(1 , 3);
            c88 = obj2(row, col +1)*mask2(2 , 3);
            c99 = obj2(row + 1, col + 1)*mask2(3 , 3);
            result = c1 + c2 + c3 +c4 +c5+ c6+ c7+ c8 +c9;
            result2 = c11 + c22 + c33 + c44 + c55 + c66 + c77 + c88 + c99;
            %result = double(result);
            %result2 = double(result2);
            rim1(row, col) = ((result^2+result2^2) *1/2);
            rim2(row, col) = atan(result/result2);
        end
    end
    writeVideo(write, rim2); %This line has the problem with rim2 as rim2 is the frame i'm trying to write on the video file.
end
close(write);